High-Resolution Maps of Mouse Reference Populations.

Area of Science:

• Genetics
• Genomics
• Comparative Genomics

Background:

• Genetic reference panels are crucial for mapping complex traits in model organisms like mice.
• Existing genetic maps provide foundational data but can be improved with higher resolution.

Purpose of the Study:

• To generate high-resolution genetic maps for multiple mouse strain panels.
• To identify genetic variations, including heterozygosity and structural changes, within these strains.
• To enhance the precision of recombination breakpoint localization for future genetic studies.

Main Methods:

• Genotyping of 259 mice from recombinant inbred and chromosome substitution strain panels using the Affymetrix Mouse Diversity Array.
• Analysis of genotyping data to construct high-resolution genetic maps with average intermarker spacing of 4.3 kb.
• Identification of residual heterozygosity, de novo deletions/duplications, and gene conversions.

Main Results:

• Generated new, high-resolution genetic maps for six mouse strain panels.
• Discovered residual heterozygosity in 40% of mice across five panels.
• Identified de novo deletions/duplications (21 kb to 8.4 Mb), with 64% overlapping protein-coding exons.
• Detected 29 gene conversions in chromosome substitution strains, more frequent in homologous regions with higher similarity.

Conclusions:

• The new genetic maps offer improved precision for localizing recombination breakpoints.
• Unexpected genetic variations, including heterozygosity and structural changes, are prevalent in commonly used mouse strains.
• These findings have significant implications for quantitative trait locus (QTL) mapping and understanding genotype-phenotype relationships in mice.